<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>js测试</title>
</head>
<body>
<div>
    <span>随便写一个标签</span>
</div>
<script>
    alert("script一般写在body的最下面,因为网页从上到下加载,先加载静态内容再动态展示");
</script>
<script src="../js/demo.js"></script>
<script src="../js/print.js"></script>
</body>
</html>